Hello everyone! I am treating cre-lox mice with tamoxifen (0.1mg/g for 5 days), and a lot of them die within the 5 days of injection, also the control mice (floxed with no cre). Is it normal? How can avoid that? Is it too much tamoxifen?
Thank you!
No, they should not die. Tamoxifen is very hard to dissolve though, so check the method you dissolve it with. In my case, just putting it in corn oil didn't work. I had to dissolve in EtOH first, then dissolve this solution in corn oil very thoroughly, then evaporate EtOH. Only then I got a good solution.
Another version why: when you do the injection you hit something or otherwise damage the mice. Then you would need someone to check your technique or if you don't have anyone, try Youtube-searching mouse intraperitoneal injection.
Yulia Panina is right. Your mice should not die. Make sure you are using the right tamoxifen for in vivo use. In my experience this Tamoxifen works very well for use in mice:
https://www.sigmaaldrich.com/catalog/product/sigma/t5648?lang=en®ion=US
Dissolve the tamoxifen in corn oil and heat it at 37°C while rotating, or shaking for about 30-45min before each use. The dissolved tamoxifen should be protected from light. Have you tried to inject corn oil without tamoxifen as a negative control? If your mice still die after just corn oil injection, you might want to double-check your injection technique as Yulia suggested.
Patrick Raedler Yulia Panina thank you very much for your answer. I use that sigma tamoxifen and I dissolve as you told. I never use corn oil as control, but with other kind of ip (for exemple anesthesia) they never die, so I don't think it's the technique.